diff --git a/pytriqs/gf/local/gf_desc.py b/pytriqs/gf/local/gf_desc.py
index f1c458e0..0169aca0 100644
--- a/pytriqs/gf/local/gf_desc.py
+++ b/pytriqs/gf/local/gf_desc.py
@@ -218,7 +218,7 @@ def make_gf( py_type, c_tag, is_complex_data = True, is_im = False, has_tail = T
             serializable= "tuple",
             is_printable= True,
             hdf5 = True,
-            arithmetic = ("algebra",data_type)
+            arithmetic = ("algebra",data_type, "with_inplace_operators")
             )
 
     g.add_constructor(signature = "(gf_mesh<%s> mesh, mini_vector<size_t,2> shape, std::vector<std::vector<std::string>> indices = std::vector<std::vector<std::string>>{}, std::string name = "")"%c_tag, python_precall = "pytriqs.gf.local._gf_%s.init"%c_tag)
@@ -372,6 +372,11 @@ g.add_method(name = "set_from_legendre",
 g.add_pure_python_method("pytriqs.gf.local._gf_imfreq.replace_by_tail")
 g.add_pure_python_method("pytriqs.gf.local._gf_imfreq.fit_tail")
 
+# For legacy Python code : authorize g + Matrix
+#g.number_protocol['add'].add_overload(calling_pattern = "+", signature = "gf<imfreq>(gf<imfreq> x,matrix<std:complex<double>> y)")
+g.number_protocol['inplace_add'].add_overload(calling_pattern = "+=", signature = "void(gf_view<imfreq> x,matrix<std::complex<double>> y)")
+g.number_protocol['inplace_subtract'].add_overload(calling_pattern = "-=", signature = "void(gf_view<imfreq> x,matrix<std::complex<double>> y)")
+
 module.add_class(g)
 
 ########################
diff --git a/pytriqs/wrap_generator/wrap_generator.py b/pytriqs/wrap_generator/wrap_generator.py
index 3e040f9a..d6b73154 100644
--- a/pytriqs/wrap_generator/wrap_generator.py
+++ b/pytriqs/wrap_generator/wrap_generator.py
@@ -269,6 +269,11 @@ class class_ :
                           - with_unit :  +/- of an element with a scalar (injection of the scalar with the unit)
                           - with_unary_minus  : implement unary minus
                  - "add_only" : implements only +
+                 - with_inplace_operators  : option to deduce the +=, -=, ...
+                   operators from +,-, .. It deduces the possibles terms to put at the rhs, looking at the
+                   case of the +,- operators where the lhs is of the type of self.
+                   NB : The operator is mapped to the corresponding C++ operators (for some objects, this may be faster)
+                   so it has to be defined in C++ as well....
                  - .... more to be defined.
         - serializable : Whether and how the object is to be serialized.  Possible values are :
              - "tuple" : reduce it to a tuple of smaller objects, using the
@@ -309,6 +314,7 @@ class class_ :
           # read the with_... option and clean them for the list
           with_unary_minus = 'with_unary_minus' in arithmetic
           with_unit = 'with_unit' in arithmetic
+          with_inplace_operators = 'with_inplace_operators' in arithmetic
           arithmetic = [x for x in arithmetic if not x.startswith("with_")]
           add =  arithmetic[0] in ("algebra", "abelian_group", "vector_space", "only_add")
           abelian_group = arithmetic[0] in ("algebra",  "abelian_group", "vector_space")
@@ -359,6 +365,23 @@ class class_ :
                 neg.add_overload (calling_pattern = "-", signature = {'args' :[(self.c_type,'x')], 'rtype' : self.c_type})
                 self.number_protocol['negative'] = neg
 
+          if with_inplace_operators : self.deduce_inplace_arithmetic()
+
+    def deduce_inplace_arithmetic(self) :
+        """Deduce all the +=, -=, *=, /= operators from the +, -, *, / operators"""
+        def one_op(op, name, iname) :
+            if name not in self.number_protocol : return
+            impl = pyfunction(name = iname, arity = 2)
+            for overload in self.number_protocol[name].overloads :
+                x_t,y_t = overload.args[0][0], overload.args[1][0]
+                if x_t == self.c_type : # only when first the object
+                  impl.add_overload (calling_pattern = op+"=", signature = {'args' : [(x_t,'x'), (y_t,'y')], 'rtype' :overload.rtype})
+            self.number_protocol['inplace_'+name] = impl
+        one_op('+',"add","__iadd__")
+        one_op('-',"subtract","__isub__")
+        one_op('*',"multiply","__imul__")
+        one_op('/',"divide","__idiv__")
+
     def add_constructor(self, signature, calling_pattern = None, python_precall = None, python_postcall = None, build_from_regular_type_if_view = True, doc = ''):
         """
         - signature : signature of the function, with types, parameter names and defaut value
diff --git a/pytriqs/wrap_generator/wrapper.mako.cpp b/pytriqs/wrap_generator/wrapper.mako.cpp
index 5fac2508..54f9a9f3 100644
--- a/pytriqs/wrap_generator/wrapper.mako.cpp
+++ b/pytriqs/wrap_generator/wrapper.mako.cpp
@@ -939,8 +939,14 @@ static PyObject * ${c.py_type}_${op_name} (PyObject* v, PyObject *w){
   %for overload in op.overloads :
   if (convertible_from_python<${overload.args[0][0]}>(v,false) && convertible_from_python<${overload.args[1][0]}>(w,false)) {
    try {
-    ${regular_type_if_view_else_type(overload.rtype)} r = convert_from_python<${overload.args[0][0]}>(v) ${overload._get_calling_pattern()} convert_from_python<${overload.args[1][0]}>(w);
-    return convert_to_python(std::move(r)); // in two steps to force type for expression templates in C++
+    %if not op_name.startswith("inplace") :
+     ${regular_type_if_view_else_type(overload.rtype)} r = convert_from_python<${overload.args[0][0]}>(v) ${overload._get_calling_pattern()} convert_from_python<${overload.args[1][0]}>(w);
+     return convert_to_python(std::move(r)); // in two steps to force type for expression templates in C++
+    %else:
+     convert_from_python<${overload.args[0][0]}>(v) ${overload._get_calling_pattern()} convert_from_python<${overload.args[1][0]}>(w);
+     Py_INCREF(v);
+     return v;
+    %endif
    }
    CATCH_AND_RETURN("in calling C++ overload \n  ${overload._get_c_signature()} \nin implementation of operator ${overload._get_calling_pattern()} ", NULL)
   }
diff --git a/test/pytriqs/base/CMakeLists.txt b/test/pytriqs/base/CMakeLists.txt
index 870f7fd5..3d074d33 100644
--- a/test/pytriqs/base/CMakeLists.txt
+++ b/test/pytriqs/base/CMakeLists.txt
@@ -17,3 +17,7 @@ add_triqs_test_hdf(dos " -d 1.e-6")
 
 # Pade approximation
 add_triqs_test_hdf(pade " -d 1.e-6")
+
+# Bug fix #112
+add_triqs_test_txt(gf_inplace_112)
+
diff --git a/test/pytriqs/base/gf_inplace_112.output b/test/pytriqs/base/gf_inplace_112.output
new file mode 100644
index 00000000..a7971b2f
--- /dev/null
+++ b/test/pytriqs/base/gf_inplace_112.output
@@ -0,0 +1,12 @@
+Before:
+G['up'] = 3.14159265359j
+G['dn'] = 3.14159265359j
+After G['up'] += G['dn']:
+G['up'] = 6.28318530718j
+G['dn'] = 3.14159265359j
+After g_up += g_dn:
+G['up'] = 9.42477796077j
+G['dn'] = 3.14159265359j
+After G += G:
+G['up'] = 18.8495559215j
+G['dn'] = 6.28318530718j
diff --git a/test/pytriqs/base/gf_inplace_112.py b/test/pytriqs/base/gf_inplace_112.py
new file mode 100644
index 00000000..66c92c69
--- /dev/null
+++ b/test/pytriqs/base/gf_inplace_112.py
@@ -0,0 +1,55 @@
+# Test from I. Krivenko.
+from __future__ import print_function
+from pytriqs.gf.local import *
+from pytriqs.gf.local.descriptors import *
+import sys
+def print_err(*x) : print (*x, file= sys.stderr)
+
+g_up = GfImFreq(indices = [0], beta = 1)
+g_dn = GfImFreq(indices = [0], beta = 1)
+
+g_up <<= iOmega_n
+g_dn <<= iOmega_n
+
+G = BlockGf(name_list=['up','dn'], block_list=[g_up,g_dn], make_copies=False)
+
+print("Before:")
+print("G['up'] =", G['up'].data[0,0,0]) 
+print("G['dn'] =", G['dn'].data[0,0,0]) 
+print_err('id(g_up) =', id(g_up))
+print_err('id(g_dn) =', id(g_dn))
+print_err ("(id=", id(G['up']),")")
+print_err ("(id=", id(G['dn']),")")
+
+G['up'] += G['dn']
+
+print("After G['up'] += G['dn']:")
+print("G['up'] =", G['up'].data[0,0,0])
+print("G['dn'] =", G['dn'].data[0,0,0])
+print_err('id(g_up) =', id(g_up))
+print_err('id(g_dn) =', id(g_dn))
+print_err ("(id=", id(G['up']),")")
+print_err ("(id=", id(G['dn']),")")
+
+
+g_up += g_dn
+
+print("After g_up += g_dn:")
+print("G['up'] =", G['up'].data[0,0,0])
+print("G['dn'] =", G['dn'].data[0,0,0])
+print_err('id(g_up) =', id(g_up))
+print_err('id(g_dn) =', id(g_dn))
+print_err ("(id=", id(G['up']),")")
+print_err ("(id=", id(G['dn']),")")
+
+
+G += G
+print("After G += G:")
+print("G['up'] =", G['up'].data[0,0,0])
+print("G['dn'] =", G['dn'].data[0,0,0])
+print_err('id(g_up) =', id(g_up))
+print_err('id(g_dn) =', id(g_dn))
+print_err ("(id=", id(G['up']),")")
+print_err ("(id=", id(G['dn']),")")
+
+
diff --git a/triqs/gfs/gf.hpp b/triqs/gfs/gf.hpp
index 06f07625..e366e3ec 100644
--- a/triqs/gfs/gf.hpp
+++ b/triqs/gfs/gf.hpp
@@ -668,8 +668,8 @@ namespace gfs {
  // auxiliary function : invert the data : one function for all matrix valued gf (save code).
  template <typename A3> void _gf_invert_data_in_place(A3 && a) {
   for (int i = 0; i < first_dim(a); ++i) {// Rely on the ordering 
-   auto v = a(i, arrays::range(), arrays::range());
-   v = inverse(v);
+   auto v = make_matrix_view(a(i, arrays::range(), arrays::range()));
+   v = triqs::arrays::inverse(v);
   }
  }
 
diff --git a/triqs/gfs/gf_expr.hpp b/triqs/gfs/gf_expr.hpp
index b6b69e30..5f659cfc 100644
--- a/triqs/gfs/gf_expr.hpp
+++ b/triqs/gfs/gf_expr.hpp
@@ -142,6 +142,26 @@ namespace triqs { namespace gfs {
    >::type
    operator - (A1 && a1) { return {std::forward<A1>(a1)};} 
 
+// Now the inplace operator. Because of expression template, there are useless for speed
+// we implement them trivially.
+
+#define DEFINE_OPERATOR(OP1, OP2)                                                                                                \
+ template <typename Variable, typename Target, typename Opt, typename T>                                                         \
+ void operator OP1(gf_view<Variable, Target, Opt> g, T const &x) {                                                               \
+  g = g OP2 x;                                                                                                                   \
+ }                                                                                                                               \
+ template <typename Variable, typename Target, typename Opt, typename T>                                                         \
+ void operator OP1(gf<Variable, Target, Opt> &g, T const &x) {                                                                   \
+  g = g OP2 x;                                                                                                                   \
+ }
+
+ DEFINE_OPERATOR(+=, +);
+ DEFINE_OPERATOR(-=, -);
+ DEFINE_OPERATOR(*=, *);
+ DEFINE_OPERATOR(/=, / );
+
+#undef DEFINE_OPERATOR
+
 }}//namespace triqs::gf
 #endif
 
diff --git a/triqs/gfs/imfreq.hpp b/triqs/gfs/imfreq.hpp
index 6923c8ef..ac175997 100644
--- a/triqs/gfs/imfreq.hpp
+++ b/triqs/gfs/imfreq.hpp
@@ -166,5 +166,17 @@ namespace gfs {
   template <typename Opt> struct data_proxy<imfreq, scalar_valued, Opt> : data_proxy_array<std::complex<double>, 1> {};
 
  } // gfs_implementation
+
+ // specific operations (for legacy python code).
+ // +=, -= with a matrix
+ inline void operator+=(gf_view<imfreq> g, arrays::matrix<std::complex<double>> m) {
+  for (int u = 0; u < first_dim(g.data()); ++u) g.data()(u, arrays::ellipsis()) += m;
+  g.singularity()(0) += m;
+ }
+
+ inline void operator-=(gf_view<imfreq> g, arrays::matrix<std::complex<double>> m) {
+  for (int u = 0; u < first_dim(g.data()); ++u) g.data()(u, arrays::ellipsis()) -= m;
+  g.singularity()(0) -= m;
+ }
 }
 }
diff --git a/triqs/gfs/local/tail.hpp b/triqs/gfs/local/tail.hpp
index a8a893da..b665403f 100644
--- a/triqs/gfs/local/tail.hpp
+++ b/triqs/gfs/local/tail.hpp
@@ -393,5 +393,19 @@ namespace triqs { namespace gfs { namespace local {
   template<typename T1, typename T2> TYPE_ENABLE_IF(tail,mpl::and_<LocalTail<T1>, is_scalar_or_element<T2>>)
     operator - (T1 const & t, T2 const & a) { return (-a) + t;}
 
+// inplace operators
+#define DEFINE_OPERATOR(OP1, OP2)                                                                                                \
+ template <typename T> void operator OP1(tail_view g, T &&x) { g = g OP2 x; }                                                    \
+ template <typename T> void operator OP1(tail &g, T &&x) { g = g OP2 x; }
+
+ DEFINE_OPERATOR(+=, +);
+ DEFINE_OPERATOR(-=, -);
+ DEFINE_OPERATOR(*=, *);
+ DEFINE_OPERATOR(/=, / );
+
+#undef DEFINE_OPERATOR
+
+  
+
 }}}
 #endif
diff --git a/triqs/parameters/parameters.hpp b/triqs/parameters/parameters.hpp
index d5f0fd5a..88ba49d2 100644
--- a/triqs/parameters/parameters.hpp
+++ b/triqs/parameters/parameters.hpp
@@ -146,6 +146,11 @@ namespace params {
   return p1;
  }
 
+ inline parameters & operator+=(parameters & p1, parameters const& p2) {
+  p1.update(p2);
+  return p1;
+ }
+
  // can only be implemented after complete declaration of parameters
  template <typename... T> _field& _field::add_field(T&&... x) {
   auto* pp = dynamic_cast<_data_impl<parameters>*>(p.get());